1. Field of the Invention
The present invention relates to a technique for collecting ink mist in an inkjet apparatus which jets out ink droplets toward a recording surface of a strip-shaped base material while transporting the base material.
2. Description of the Background Art
An inkjet apparatus which records an image on a surface of a strip-shaped base material by jetting out ink from a plurality of heads while transporting the base material has heretofore been known. When the inkjet apparatus of this type jets out ink from the heads, fine ink mist is produced. If diffused in an enclosure of the inkjet apparatus, the ink mist adheres to electronic components, mechanical components and the like in the enclosure to result in the danger of a contact failure of connectors and the reduction in lifetime of components. To solve such a problem, a variety of techniques have heretofore been proposed to collect ink mist by suction.
For example, an inkjet printer including a mist suction unit disposed downstream in the transport direction of a paper transport unit is disclosed in Japanese Patent Application Laid-Open No. 2010-201873 (paragraph 0019 and FIG. 4). As another example, an inkjet apparatus including an exhaust part provided near a medium which has not yet been struck by ink from heads and for suctioning gases is disclosed in Japanese Patent Application Laid-Open No. 2013-119218 (paragraph 0038 and FIG. 1).
Unfortunately, when a strip-shaped base material is transported, an airflow referred to as a viscous flow is produced near the surface of the base material. The ink mist contained in this viscous flow is not separated from the surface of the base material by suction only. It has hence been difficult for the structures disclosed in Japanese Patent Application Laid-Open No. 2010-201873 and Japanese Patent Application Laid-Open No. 2013-119218 to sufficiently collect the ink mist contained in the viscous flow. For the collection of the ink mist contained in such a viscous flow, there has been a need to forcefully separate the viscous flow from the surface of the base material by means of an air knife.
In particular, the force required to separate the viscous flow from the surface of the base material increases with the increase in the speed of transport of printing paper. Therefore, the technique for collecting the ink mist contained in the viscous flow becomes more important as the processing capability of the inkjet apparatus increases.